Influence of very Low Temperatures on Germinative Power. 165 



Rotifera, and also by some recent experiments of Yan Ejck on dis- 

 continuous germination,* that ordinary protoplasts may, by suitable 

 treatment, be brought to the " resting " condition. 



In 1871, Lord Kelvin, in his Presidential Address to the British 

 Association, threw out the suggestion that the origin of life as we 

 know it may have been extra-terrestrial, and due to the "moss-grown 

 fragments from the ruins of another world," which reached the 

 earth as meteorites.! That such fragments might circulate in the 

 intense cold of space for a perfectly indefinite period without pre- 

 judice to their freight of seeds or spores, is almost certain from the 

 facts we know about the maintenance of life by " resting " proto- 

 plasm ; the difficulties in the way of accepting such a hypothesis 

 certainly do not lie in this direction. 



We must express our thanks to Mr. Thiselton-Dyer and to 

 Dr. D. H. Scott, for the facilities they have given us in carrying out 

 these experiments in the Jodrell Laboratory. 



Addendum. 



After the completion of the above Note, our attention was called to a 

 recent investigation by M. R. Chodat, on the influence of low tempera- 

 tures on Mucor mucedo.% He found that a lowering of temperature for 

 several hours to —70° to -—110° C. failed to kill young spores of the 

 mucor, and he adduces certain evidence, which is not, however, wholly 

 convincing, that even the mycelium itself, when cultivated on Agar- 

 Agar, and whilst in active growth, is able to resist the action of these 

 low temperatures. The author sums up his opinion as to the bearing 

 of his experiments on the nature of life in the following words : — 

 " La respiration elle-meme est evidemment completement arretee a 

 cette temperature ou les corps chimiques ne reagissent plus les uns 

 sur les autres. Si Ton considere que la vie consiste principalement 

 en un echange continuel de substance, soit par la nutrition intra- 

 cellulaire, soit par la respiration, alors il faut convenir qu'a ces tem- 

 peratures basses la vie n'existe plus. C'est une fatale erreur qu'on 

 rencontre dans presque tous les traites que la respiration est une 

 condition necessaire de la vie, alors qu'elle n'est qu'une des con- 

 ditions de sa manifestation. La vie est conditionnee par certaines 

 structures. Les forces qui les mettent en jeu peuvent etre des forces 

 toutes physiques. Biles sont simplement les sources d'energie qui 

 pourront mettre la machine en mouvement." 



* ' Aim. Agron.,' vol. 21 (1895), p. 236. 



f We find that Professor Dewar called attention in one of his Boyal Institution 

 lectures in 1892 to the bearing of his low temperature experiments with spores, 

 &c, on this suggestion of Lord Kelvin's (see 4 Hoy. Inst. Proc.,' 1892, vol. 13,. 

 p. 699). 



X ' Bulletin de l'Herbier Boisier,' vol. 4 (1896), p. 894. 



